Contrary to popular belief in the developed world, there are quite a few animals that will gladly prey on susceptible humans. These include Saltwater Crocodiles, the grey wolf, Great White Shark, tigers, and several others. In the last two centuries, tens of thousands of humans have died from attacks by these animals, especially tigers and crocodiles. But, by and large, humans reign over these animals with tools like guns and traps. This was not always the case, as there are many extinct predators of humans that would have terrorized humanity as the giant crocodile Gustave today terrorizes the natives in places like Lake Tangianyika in Burundi.
This article will focus on three extinct likely predators of humans -- the Cave Hyena, Dire Wolf, and the giant Australian lizard Megalania. All these animals existed for over a million years and went extinct between 40,000 and 9,000 years ago, strongly suggesting that humans were the agent of extinction.
The Cave Hyena was an subspecies of the Spotted Hyena that lived in caves throughout Eurasia, including as far north as Beringia. Cave hyenas, being subspecies of modern hyena, were around the same size and intelligence, but on average they had stronger hindquarters, which initially caused them to be categorized as a separate species. Like modern hyenas, which occasionally prey on human children, the cave hyenas would have been predators of humans, and would have competed with them for caves. Caves with alternating cycles of Neanderthal and cave hyena bones have been discovered, and cave hyenas have been implicated as a delaying factor in human migration from Eurasia into North America.
The Dire Wolf was a larger relative of the Grey Wolf with larger teeth and sharper carnassals, which would have been used to sever bone, evidenced by extensive tooth wear on many Dire Wolf fossils. The Dire Wolf lived in the Americas, unlike the Grey Wolf which is native to Eurasia. The Dire Wolf had a smaller braincase than modern wolves, which suggested it was less intelligent. Its status among predators of humans is implicated by its evolutionary relationship to modern wolves, some of which consume humans when they get the chance. In ancient North America, Dire Wolves would have competed closely with humans for food and land.
Another of the likely predators of humans is the giant lizard Megalania, related to the modern Komodo Dragon but more than twice as large. Modern Komodo Dragons have been observed stalking humans and attacking children, making it likely that Megalania would have exhibited the same behavior. Megalania is the largest lizard that ever lived, reaching 7 m (23 ft) in length and weighing 620 kg (1,400 lb). Unlike mammalian predators, it would have had a slow metabolism, and was probably an ambush predator. In a long chase, humans would have surely gotten away, but if they didn't see what was coming, they would be bitten by the lizard's two-foot jaws, which were likely covered in poison like the jaws of the Komodo Dragon. This would have led to an agonizing death.